Apr 30, 2020
1 scrap rate
Definition: This percentage is obtained by dividing the cost of scrap materials by the total production cost or the total quantity of scrap divided by the total production quantity of the product.
Purpose: To be used as a result measure to determine whether the process is standardized for parts production and assembly.
• Amount of waste materials: is the value of the materials used for waste.
• Total production cost: It is the sum of labor, materials and factory burden (water, electricity, etc.).
• Application / Information: The scrap calculation is to get its value directly from the financial system of the unit. If the company's financial system cannot separate the value of waste materials from labor and burden, it should be coordinated with relevant departments as soon as possible.
2 Rework rate
Definition: The proportion of time spent in rework activities is obtained by dividing the rework hours by the production labor hours or the total number of rework (rework) products divided by the total production quantity.
Purpose: Used as a measure of results to emphasize those operating stations that need improvement in the first quality.
• Rework time: refers to the time it takes to process, sort, and repair those parts that will become scrap. These times can be spent on work-in-progress, finished products and purchased parts or materials. Rework time includes things like repairs, repackaging, re-sorting, additional inspection activities and containment. Rework time includes internal or external activities. It should include the direct time plus the direct time portion of overtime.
• Production working hours: the sum of working hours of direct / productive workers (including direct time plus the direct time part of overtime hours).
• Application / information: Occasional inspections of direct workers should not be considered rework. Any product that re-enters the production process should be considered reworked. Part of the total labor content of the production line should be considered rework. This part will be determined according to the reworked products. During the final inspection, 10% of the products in the paint production line are unqualified, and the paint production line has 20 operators. The reworked products (10%) need to be painted again. 10% of the total working time of the paint production line is considered to be used for rework. 10% × 20 people × 8 hours = 16 rework hours.
3Qualification rate of product storage inspection
Definition: The qualified quantity of product storage inspection divided by the total quantity of storage inspection.
Purpose: Used as a process metric to measure the quality level of the entire production process.